Add a few drops of peppermint essence and the icing sugar (and the food
colouring if using) and mix well to form a stiff paste. Dust the work
surface, your hands and a rolling-pin with icing sugar and roll out the
paste to 0.5cm thick. Use small cutters to cut out shapes and place on a
tray or plate in the fridge for 3-4 hours until set.